Then there are few players (which are basically frond-ends) that use both those "engines". Gxmms2 is such as player frond-end and then there was Abraca. The reason I said "was" because it seems at the moment that the player GUI is no longer being developed (perhaps it has all the intended features after all).
Remember with Abraca ... if you have thousands of audio files... it won't make it that easy on you. The main GUI is divided into main three sections.
Left side - Lets you manage playlists, Middle - Lets you search and displays the results (filtering) and the Right side - that's the real playlist.
*. Since it's based on Xmms2, it should play any file supported by Xmms - mp3, mp4, vorbis, aac, alac, wma, mac, sid, mod, wav, flac, mpc, speex, wavpack,, etc.
*. Add individual files/folders or URLs.
*. Read MP3 Tags.
*. Cover-art support.
You can install Abraca in Ubuntu 11.04 Natty Narwhal (should also work on 10.04 and 10.10) by using the below command in your Terminal window.
sudo apt-get abracaOn the bright side it's pretty fast but this is certainly not the best one if you have to handle albums + I personally find it a bit confusing. In that case, if you're looking for a fast loading, minimalistic player then I highly recommend that you give a try at the awesome Beatbox instead.